[1] Field of the Invention
The present invention relates to high-frequency on-off valves that frequently open and close output orifices by bringing valve members, which have a small opening-closing stroke, into and out of contact with valve seats.
[2] Description of the Related Art
Patent Literatures, Japanese Unexamined Patent Application Publication No. 2004-332876 and Japanese Unexamined Patent Application Publication No. 2006-329335, for example, each disclose a known high-frequency on-off valve of the aforementioned type. A high-frequency on-off valve is used for, for example, sorting articles and is configured to open and close an output orifice by bringing a plate-shaped valve member into and out of contact with a valve seat so as to output a pressure fluid from the output orifice toward an article to be sorted at high speed. However, since the opening-closing stroke of the valve member is small (e.g., about 0.1 mm), it is difficult to obtain a good balance between the responsiveness of the valve member and the flow rate characteristics of the output fluid. If the opening-closing stroke of the valve member is to be reduced for enhancing the responsiveness, the opening amount of the output orifice decreases, resulting in poor flow rate characteristics. In contrast, increasing the opening-closing stroke of the valve member for enhancing the flow rate characteristics results in poor responsiveness. Furthermore, increasing the opening area of the output orifice itself hardly contributes to an improvement in flow rate characteristics since the flow rate of the output fluid depends on the opening amount of the output orifice by the valve member, that is, the area of a gap (i.e., a valve opening) formed between the valve member and the valve seat.
The high-frequency on-off valve of this type is also commonly used under conditions that require an output fluid with a high flow rate. Therefore, a new high-frequency on-off valve that can obtain an output fluid with a flow rate higher than that in the high-frequency on-off valve in the related art is desired.